Don't create parallel request until download file is initialized

content/browser/download/download_item_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // File method ordering: Methods in this file are in the same order as
 // in download_item_impl.h, with the following exception: The public
 // interface Start is placed in chronological order with the other
 // (private) routines that together define a DownloadItem's state
 // transitions as the download progresses.  See "Download progression
 // cascade" later in this file.
@@ skipping 1045 matching lines @@
   content_disposition_ = new_create_info.content_disposition;
   // It is possible that the previous download attempt failed right before the
   // response is received. Need to reset the MIME type.
   mime_type_ = new_create_info.mime_type;
 
   // Don't update observers. This method is expected to be called just before a
   // DownloadFile is created and Start() is called. The observers will be
   // notified when the download transitions to the IN_PROGRESS state.
 }
 
-void DownloadItemImpl::CancelRequestWithOffset(int64_t offset) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  if (job_)
-    job_->CancelRequestWithOffset(offset);
-}
-
 void DownloadItemImpl::NotifyRemoved() {
   for (auto& observer : observers_)
     observer.OnDownloadRemoved(this);
 }
 
 void DownloadItemImpl::OnDownloadedFileRemoved() {
   file_externally_removed_ = true;
   DVLOG(20) << __func__ << "() download=" << DebugString(true);
   UpdateObservers();
 }
@@ skipping 235 matching lines @@
   // If the download uses parallel requests, and choose not to create parallel
   // request during resumption, clear the received_slices_ vector.
   if (!IsParallelDownloadEnabled() && !received_slices_.empty()) {
     received_bytes_ =
         GetMaxContiguousDataBlockSizeFromBeginning(received_slices_);
     received_slices_.clear();
   }
 
   TransitionTo(TARGET_PENDING_INTERNAL);
 
-  job_->Start();
-}
-
-void DownloadItemImpl::StartDownload() {
-  BrowserThread::PostTask(
-      BrowserThread::FILE, FROM_HERE,
-      base::Bind(&DownloadFile::Initialize,
-                 // Safe because we control download file lifetime.
-                 base::Unretained(download_file_.get()),
-                 base::Bind(&DownloadItemImpl::OnDownloadFileInitialized,
-                            weak_ptr_factory_.GetWeakPtr()),
-                 base::Bind(&DownloadItemImpl::CancelRequestWithOffset,
-                            weak_ptr_factory_.GetWeakPtr()),
-                 received_slices_, job_ && job_->IsParallelizable()));
+  job_->Start(download_file_.get(),
+              base::Bind(&DownloadItemImpl::OnDownloadFileInitialized,
+                         weak_ptr_factory_.GetWeakPtr()),
+              GetReceivedSlices());
 }
 
 void DownloadItemImpl::OnDownloadFileInitialized(
     DownloadInterruptReason result) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK(state_ == TARGET_PENDING_INTERNAL ||
          state_ == INTERRUPTED_TARGET_PENDING_INTERNAL)
       << "Unexpected state: " << DebugDownloadStateString(state_);
 
   DVLOG(20) << __func__
@@ skipping 950 matching lines @@
     case RESUME_MODE_USER_CONTINUE:
       return "USER_CONTINUE";
     case RESUME_MODE_USER_RESTART:
       return "USER_RESTART";
   }
   NOTREACHED() << "Unknown resume mode " << mode;
   return "unknown";
 }
 
 }  // namespace content